During repair or replacement of exhaust systems for motor vehicles or the like, it is frequently necessary to effect expansion of end portions of tubing to accommodate assembly with associated components. In this manner, a closely fitting, overlapping joint can be formed between adjacent sections of tubing, thereby eliminating the need for separate adapters. The ability to expand tubing in this manner greatly facilitates repair or replacement of exhaust systems. Naturally, expansion of tubing can also facilitate joining of tubular sections in applications apart from exhaust system service.
An apparatus which has proven particularly effective for efficiently expanding tubing is illustrated in U.S. Pat. No. 3,385,087, to Huth. This patent discloses a swaging tool for effecting tubing expansion, which includes a fluid-operated ram operatively connected to an expander, with the expander being adapted to coact with a plurality of jaw segments disposed about the expander. The tool is operated by positioning the jaw segments within the end portion of a piece of tubing, and by stroking the fluid ram so that the jaw segments are urged outwardly to effect expansion of the tubing. Portions of this patent not inconsistent with the present disclosure are herein incorporated by reference.
While the above-described expander tool is effective for expanding tubing as intended, use of the tool can sometimes be inconvenient. In the past, tools of this nature have typically been supplied with pressurized fluid for their operation from a foot-operated fluid supply unit. The fluid supply unit typically comprises a device which is provided with pressurized air, and which utilizes the pressurized air for pressurizing hydraulic fluid which is supplied to the expander unit through a suitable conduit. For example, U.S. Pat. Nos. 4,198,844 and 4,308,736, both to Lowe et al., each illustrate a tube expander device which is described as controlled by an air-oil pump connected to a source of shop air.
As will be appreciated, expansion of tubing during exhaust system service must frequently be effected when the tubing to be expanded is positioned on an automobile or other motor vehicle. Naturally, working space is often limited, and service personnel frequently find it difficult to conveniently actuate a foot-operated fluid supply unit for the expander tool. In some instances, it can be practically impossible to properly operate the fluid supply unit while holding the expander tool in proper position to perform the expansion operation. Of further significance, a suitable source of air is not always available for operation of expander devices which employ an air-oil pump or the like, thus limiting versatility of such arrangements.
Another disadvantage of tubing expander arrangements such as described above relates to the speed with which expansion is effected. With most previous arrangements, a relatively long period of time is required for sufficient fluid pressure to be built up in the expander tool so that the desired degree of expansion is effected (typically on the order of 30 seconds or more). This further detracts from convenient operation, since the expander tool ordinarily must be held in position as it operates, and the frequently cramped working space can make holding the expander tool in position for an extended period difficult.
In order to more efficiently perform tubing expansion operations, it is highly desirable to provide an expansion apparatus which overcomes the disadvantages associated with previously known arrangements. It is particularly desirable to provide an apparatus which can be conveniently operated, which performs the expansion operation relatively quickly, and which is readily adjustable so that a user may easily select the degree of expansion to be effected for tubing of different dimensions. The present invention provides these desirable objectives with an apparatus which is very convenient to use, straightforward in construction, and highly efficient in operation.